论文总字数:23878字
摘 要
近十几年来,我国高速公路迅速发展,截止到2009年6月已经通车营运的高速公路达到7.5万km,其中大部分都采用的半刚性基层沥青路面,约占高速公路总里程的90%。这类路面通常由半刚性材料底基层、半刚性材料基层和沥青面层构成。半刚性基层具有较高的强度、刚度,并且自成板体,具有很好的荷载扩散能力,起着结构主要承重层的作用;沥青面层覆盖在半刚性基层上保持其性能的稳定,且平整、抗滑、耐磨、无接缝、行车舒适,能够较好地适应交通需求,故这种路面结构在我国的公路建设中得到了广泛的应用,目前已经成为我国高等级公路的主要路面结构形式。但是这种路面结构仍然存在一些不可避免的技术问题,因而十分有必要对这些病害的机理和形成原因进行深入研究,并在此基础上提出有效的防治措施。
本文在大量查阅了国内外相关文献以及研究资料的基础上,对于半刚性基层沥青路面的发展历史、设计方法和现状进行了分析。
首先,通过分析半刚性基层沥青路面的路面结构和应力特征,并且与其他的路面结构进行对比之后,便可以了解到半刚性基层沥青路面是最适合我国实际情况的路面结构,即它成为我国高等级公路路面主要结构形式的原因。
然后,分析评价了我国如今采用的沥青路面设计方法,提出了现用的设计指标——路表弯沉值和层底拉应力所存在的不足之处,反观国外的设计方法中一些相对更为合理的指标,根据我国路面结构的情况,对我国的沥青路面设计方法提出了一些改进建议,即不妨将如今的设计指标改为土基顶面压应变和面层层底拉应变。
最后,针对我国半刚性基层沥青路面主要的三种病害类型:水破坏、纵向变形、裂缝(其中以反射裂缝为主),研究了它们的产生原因和扩展机理,并针对其具体情况提出了相应的防治措施。
关键词:半刚性基层沥青路面;设计弯沉值;沥青路面设计方法;反射裂缝
ABSTRACT
In the recent ten years, the freeway construction of our country has been developing rapidly. The total length has come to 7.5 million km by the end of July, 2009, most of which are the semi-rigid base asphalt pavements, accounting for about 90% of the total length of freeway. This kind of road usually consists of semi-rigid material base, semi-rigid material sub-base and asphalt surface layer. Semi-rigid base that has high strength, stiffness, plate body, better ability to diffuse the load plays a role as the main load-bearing structure layer. While asphalt surface layer is covered on the semi-rigid base to maintain its performance stability, and its smoothness, sliding resistance, wear resistance, quietness and comfort of driving can better meet the traffic demand. That's the reason why this kind of construction has been widely used in our country and has become the main structure of the high-grade highway pavement. But this kind of pavement structure still exists some inevitable technical problems. The water damage, the longitudinal deformation and cracking are three main types of diseases of semi-rigid base asphalt pavement. It is necessary to deeply study the mechanism and the formation of these diseases, and put forward some effective measures of prevention and treatment.
Based on the large number of investigation of correlative references, foreign literature and research data, this paper analyzes the development history, design methods and current situation of semi-rigid base asphalt pavement.
Firstly, through the analysis of structures and stress characteristics of semi-rigid base asphalt pavement and the comparison with other pavement structures, the semi-rigid base asphalt pavement is find out to be the most suitable pavement structure for nowadays actual situation. And that's also the reason why it has become the main structure of Chinese high-grade highway pavement.
Then, after analysing and evaluating the design method of asphalt pavement that our country adopts nowadays, the shortcomings of current design index, road surface deflection value and bottom layer tensile stress, have been put forward. In contrast, some foreign design indexes are more reasonable. According to the situation of our country, the design methods of asphalt pavement need some improvement. It is suggested that the design index used in our country can be replaced by compressive strain of the sub-grade surface and tensile strain of the bottom layer.
Finally, for semi-rigid base asphalt pavement in our country, there are three main types of diseases: water damage, longitudinal deformation and cracks (especially the reflection cracking). Their reason and expansion mechanism are discussed and the corresponding resistant measures of the semi-rigid base asphalt pavements are founded.
Keywords:The semi-rigid base asphalt pavement;Design deflection value;Design methods of the asphalt pavement;Reflective cracking
摘 要 0
ABSTRACT 0
第一章 绪论 1
1.1 研究背景 1
1.2 国内外研究现状 2
1.3 研究内容、目的和意义 3
1.4 研究技术路线 3
第二章 半刚性基层沥青路面发展历史 4
2.1 沥青路面发展历史 4
2.2 半刚性基层沥青路面应力特征 7
2.2.1压应力 7
2.2.2拉应力 8
2.2.3面层中的剪应力 8
第三章 沥青路面设计方法 10
3.1我国现行沥青路面设计规范 10
3.1.1路表弯沉值的非唯一性 11
3.1.2路表弯沉值的非对应性 11
3.1.3单项指标与综合指标 11
3.2国外沥青路面设计方法评述 12
3.2.1壳牌沥青路面设计方法(Shell法) 14
3.2.2美国沥青协会(AI)沥青路面设计方法 15
3.3 我国的改进方法 16
第四章 半刚性基层沥青路面的主要病害 17
4.1水破坏 17
4.1.1产生水破坏的原因 18
4.1.2减少沥青路面水破坏的措施 18
4.2纵向形变 20
4.2.1纵向形变的产生原因 20
4.2.2 减少纵向变形的措施 20
4.3裂缝 21
4.3.1裂缝的产生原因 21
4.3.2 裂缝的防治措施 23
第五章 结论与展望 24
5.1主要结论 24
5.2有待进一步研究的问题 26
致 谢 27
参考文献 28
第一章 绪论
1.1 研究背景
自从1988年沪嘉高速公路通车之后,我国高速公路便实现了零的突破,之后我国公路的总里程数飞速增长,在2008年底达到368万公里。其中半刚性基层沥青路面占据了高等级公路,尤其是高速公路很大一部分比例,我国有近90%的高速公路采用了半刚性基层沥青路面的结构形式。
我国的沥青混凝土随着社会和交通的发展,经历了从低级到高级的发展过程。早期大多路面采用碎石铺筑,或是在原有的路面结构上加铺表面处治层或是灌入式路面。到了二十世纪八十年代,随着交通的发展,重载交通的比例日渐增大,无机结合料稳定粒料类基层开始在我国获得较为广泛的使用。进入二十世纪九十年代之后,半刚性基层沥青路面已经成为我国高等级公路的主要路面结构形式。
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